Which type of vision correction lens is designed for people who are farsighted?

Farsightedness, or hyperopia, occurs when light entering the eye is focused behind the retina. This condition makes it difficult for individuals to see nearby objects clearly, while distant objects may be seen more clearly. To correct this vision issue, convex lenses are needed.

Convex lenses are thicker in the middle and thinner at the edges, causing light rays that enter the lens to converge, or come together. This convergence helps to adjust the focal point of light rays so that they focus directly on the retina instead of behind it. By using convex lenses, people who are farsighted receive clearer vision for close-up tasks.

In contrast, other lens types serve different purposes. Aspheric lenses are designed to reduce distortion in vision across different viewing angles but do not specifically address farsightedness. Concave lenses, on the other hand, diverge light rays and are used to correct nearsightedness (myopia). Bifocal lenses contain two different optical powers to assist individuals with both distance and near vision but aren't specifically meant for correcting farsightedness on their own.

Thus, the correct choice is convex lenses, as they effectively correct the vision issues associated with being farsighted.